Reports of myocarditis and pericarditis after mRNA COVID-19 vaccination in some jurisdictions

Public Health Sudbury & Districts is carefully following investigations into reports of cases of myocarditis and pericarditis in some jurisdictions following mRNA COVID-19 vaccination (Pfizer-BioNTech and Moderna), particularly in adolescents and young adults. Public Health also wishes to advise on its processes to ensure that everyone who receives a vaccine is fully informed.

“Although all jurisdictions, including Ontario, continue to recommend COVID-19 vaccine for everyone 12 years of age and older given the risk of COVID-19 illness and related, possibly severe complications, it is important for people to be informed,” said Dr. Penny Sutcliffe, Medical Officer of Health with Public Health Sudbury & Districts. “The investigations to date have not led Ontario to change any of its vaccine guidance. As part of our vaccination program, however, all immunizers are required to share information on known or potential vaccine side effects to ensure that consent to vaccination is informed. Immunizers constantly update this information as new data is available,” explained Dr. Sutcliffe.

In May 2021, international reports of myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining around the heart) following COVID-19 mRNA vaccines emerged, including from Israel and the United States. There have been a small number of reports of myocarditis and pericarditis in Canada. Canada is not currently seeing higher rates than would be expected for these conditions.

To June 12, Public Health Ontario reported a total of 19 cases in Ontario. Currently, there is no clear association between myocarditis and pericarditis and the mRNA vaccines. Any adverse event occurring after a vaccination may be unrelated to the vaccine itself, however, all events are reported to public health to ensure ongoing review of any potential safety signals. To date, no jurisdiction has changed their vaccine guidance as a result of the reported cases of myocarditis and pericarditis.

The Public Health Agency of Canada and Health Canada are closely monitoring the situation. Available information to date indicates the following:

  • Cases were more commonly reported after the second dose
  • Symptoms typically appeared within several days following vaccination
  • Cases were mainly among adolescents and young adults
  • Cases were among males more often than females
  • Cases experienced mild illness and symptoms improved quickly (they responded well to rest and general medical—such as anti-inflammatory medications)

Locally, Public Health Sudbury & Districts is also monitoring the situation and latest evidence. Health Care Providers across the catchment area have also been advised through an Advisory Alert issued on June 18, 2021.

Informed consent is required for all vaccinations. Individuals eligible to receive a COVID-19 vaccine who have questions, are encouraged to speak with their health care provider prior to receiving an mRNA vaccine.

Reporting adverse events following immunization

All cases of any adverse event following immunization, including myocarditis or pericarditis, should be reported to Public Health Sudbury & Districts:

  • Call Public Health at 705.522.9200, ext. 458 (toll-free 1.866.522.9200) during business hours or after-hours at 705.688.4366.
  • Complete the Adverse Events Following Immunization (AEFI) Report Form available from Public Health Ontario. Fax the completed form to Public Health Sudbury & Districts’ confidential fax line at 705.677.9618 or email us at

More information

Public Health Sudbury & Districts continues to monitor the vaccines for safety and is committed to being transparent. With the Delta variant circulating in Ontario, all individuals should book an appointment for their first dose and all eligible for their second dose are encouraged to book an appointment or attend a walk-in clinic as soon as possible.

For additional information on the COVID-19 vaccines, as well as for specific answers to your frequently asked questions visit our FAQ web page or call Public Health Sudbury & Districts at 705.522.9200 (toll-free 1.866.522.9200).

This item was last modified on June 21, 2021